In recent years, an optical functional device on a silicon substrate for which a silicon electronic circuit fabrication technology with which large-scale integration can be implemented at a low cost is utilized draws attention.
Further, in a high-performance server, a supercomputer or the like, enhancement in performance is attempted by employment of a multicore configuration for a CPU (Central Processing Unit) and so forth so as to be ready for enhancement in required arithmetic operation performance. On the other hand, in communication between chips or boards, while the speed of the arithmetic operation performance is increasing, communication with an electric signal is reaching a limit from a problem of a physical distance.
A large-scale optical communication device on a silicon substrate which is based on a low-loss and small-sized silicon narrow line waveguide, namely, a silicon photonics, is expected as a technology for solving the problem of insufficiency of the communication capacity of such an information processing apparatus whose operation speed is increasing as described above.
The silicon photonics is configured from an optical functional device such as a silicon-based optical waveguide, light emitting device, light receiving device, optical modulator, optical branching unit and optical demultiplexer.
For example, as an optical modulator in the silicon photonics, it is expected that a ring optical modulator of a very small size of, for example, several 10 μm2 to 100 μm2 and a low capacity is promising from a point of view of power consumption and a high-speed responsibility.